A railway vehicle is a special vehicle operating on special rails, and when operating along the special rails, the railway vehicle can be self-oriented without being controlled in direction. A bogie is one of the most important components on the railway vehicle, and it supports the weight of an entire commodity and the weight of the vehicle body. The traditional bogies is mostly of a structure with three large parts, namely, two side frame components and a swing bolster component, guide frames on both ends of the side frame components are installed on front and back wheel pair components through axle box bearing saddles and bearing devices, and both ends of the swing bolster component are installed in central square frames of the side frame components through two groups of central suspension devices. The axle box bearing saddles and the bearing devices are movable joints contacting the side frame components with the wheel pair components, are used for converting rolling of wheels along the rail route into translation of the vehicle body along the rail route and can flexibly operate along a straight line and successfully pass by a curve.
When the railway vehicle operates at a high speed on the rails, complex impact and vibration will be produced accordingly. In order to reduce a variety of dynamic effects of unsmooth rail routes and high speed motion of wheel pairs on the vehicle body, for example, longitudinal impact, vertical vibration, lateral vibration and the like, those skilled in the art often set elastic damping devices between related vehicle members according to different vehicle conditions. For example, an elastic axle box suspension device is arranged between the guide frame of the side frame of the bogie and the wheel pair component, the elastic axle box suspension device generally includes a vertical elastic device located between the top face of the axle box bearing saddle and the bottom surface of the guide frame of the side frame and a longitudinal elastic device located between the axle box bearing saddle and the two side faces of the guide frame of the side frame, and the elastic axle box suspension device plays an important role in such aspects as whether the linear operation of the vehicle is stable, whether the vehicle can successfully pass by the curve, and guaranteeing the safe operation of the vehicle, and the like.
With the continuous increase of the load capacity of the railway vehicle, the axle weight of the vehicle increases constantly, and the operation speed of the vehicle is continuously improved, so that the requirements on the quality and performance of the vehicle bogie is also higher and higher. At a state of heavy load and high speed, when moving along the rails, the vehicle wheel pairs are easier to initiate yaw motion of the vehicle body, resulting in greatly reduced operation quality of the vehicle and will cause a vehicle derailment accident seriously. Meanwhile, when the vehicle passes by the curve, the lateral force of the wheel rail cannot be too large, otherwise, the vehicle is also possible to derail.
One of the critical components directly affecting the snaking critical operation speed of the railway vehicle on a straight line and the passing performance of the vehicle on a curve is the longitudinal elastic device in the above-mentioned elastic axle box suspension device, and the structural shape design and the elastic stiffness parameter design thereof are of vital importance. In order to increase the snaking critical operation speed of the railway vehicle on the straight line, larger longitudinal positioning stiffness thereof must be required; when the vehicle passes by the curve, to prevent an over large lateral force of the wheel rail, smaller longitudinal positioning stiffness thereof must be required.
At present, improving the snaking critical operation speed of the vehicle on the straight line and improving the passing performance of the vehicle on the curve are a pair of contradictions, and thus it is very hard to give consideration to both in the specific design of the above-mentioned longitudinal elastic device. This is because the existing elastic device is usually composed of two or more elastomers connected in series, in parallel, or in series and parallel. For example, a serial structure of three elastomers K1, K2, K3 as shown in FIG. 1, a parallel structure of three elastomers K1, K2, K3 as shown in FIG. 2 and a series-parallel structure of seven elastomers K1-K7 as shown in FIG. 3. The common feature of these elastic devices lies in that the combined stiffness is generally linear stiffness or stiffness being small at first and then becoming large, and more simply, stiffness being soft at first and then becoming hard. When being applied with an external load P, the elastomer with smaller stiffness will bear the load at first to generate a larger deformation displacement, and then the elastomer with larger stiffness bears the load to generate a smaller deformation displacement. When being specifically applied to the above-mentioned longitudinal elastic device, due to the limitation of the combined stiffness being soft at first and then becoming hard, the increase of the deformation displacement corresponds to the load linearly or in an equal proportional increase manner. In this case, the large stiffness requirement of the linear snaking critical operation speed of the vehicle and the small stiffness requirement of the curve passing performance of the vehicle cannot be completely compromised, meanwhile the risk of train derailment also exists, and thus the buffering and damping function is greatly reduced.
How to effectively improve the linear stability and the curve passing performance of the heavy-loaded vehicle operates at a high speed is always a problem attempted to be solved by those skilled in the art, and this has an important practical significance of improving the operation quality of the railway vehicle and guaranteeing the safety performance of the railway vehicle.